Burma's detained opposition leader has indicated that she believes her party should boycott a controversial poll planned for later this year – further undermining the credibility of what many believe is a "sham" election.

Aung San Suu Kyi told her lawyer she believed the National League for Democracy (NLD) should not register because a series of restrictions – including the demand that she be ousted from her party – were unjust. "Personally, I would not even think of registering [the party] under these unjust laws," Ms Suu Kyi said, according to her lawyer, Nyan Win, who met her yesterday at the crumbling house in Rangoon where she is under house arrest. "I am not instructing the party or the people. They are free to make their decisions democratically."

The military junta that controls Burma, the State Peace and Development Council (SPDC), claims that an election planned for later this year will help to move the country towards democracy. Many independent observers believe the election will simply further cement the military within the establishment of the country.

Earlier this month, the junta issued guidelines for the election that made clear that the 64-year-old Nobel laureate would not be permitted to contest the vote because she is under house arrest. The guidelines appeared to suggest that the NLD would have to expel her if it wanted to take part. The party has called a meeting of its senior members for next Monday when it will announce its decision. The statement by Ms Suu Kyi will be hugely influential.

Derek Tonkin, a former British ambassador in South-east Asia and head of the Myanmar Network, said that if the NLD voted not to participate, those members wishing to take part would have to leave and form a different party. "[If the NLD does not participate] it will make it much harder for the junta to sell the election to the West," he added. The last democratic election in Burma was held in 1990 and the NLD won by a landslide. The junta refused to accept the result and embarked on a fresh round of political repression, jailing hundreds of its opponents.

Ms Suu Kyi has spent 14 of the last 20 years in jail or under house arrest, the term of which was extended last year after she was convicted of breaching the conditions of her detention when an uninvited American visitor swam across a nearby lake to her home. Most independent observers believe the charges against her were brought simply to keep her out of the way until the conclusion of the election, which many expect to be held in October.

The statement by the NLD leader, who had not previously indicated whether she believed her party should participate, came as her lawyers sought to overturn regulations banning her from taking part. Her legal team tried to file a petition with the country's Supreme Court to challenge the election regulations announced earlier this month. The court refused to accept the petition, saying it was not qualified to hear the case.

David Mathieson, a Burma expert at Human Rights Watch, told Agence France-Presse: "The NLD has got to decide whether to adapt to the deeply unfair situation and try to contest in some way or take the moral high ground and continue to be excluded."

The UN's special envoy, Tomas Ojea Quintana, recently called for an inquiry into whether the regime was guilty of war crimes and crimes against humanity, something the authorities angrily rejected. He also renewed calls for the junta to release more than 2,100 political prisoners, including Ms Suu Kyi, ahead of the polls.

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